It has been known heretofore to provide electrically driven portable surface-treating machines such as sanders, polishers, buffers and the like with an oscillatable platen which is connected to the housing of the machine through the securement to a plurality of resilient posts. In the past, whether the post was mechanically connected at one or both ends, either metal inserts were required or external brackets were used to hold the adjacent pairs of resilient posts in position. This resulted in increased costs and a more complex structure leading to assembly difficulties.